Disconnect mechanism



April 29, 1958 L. H. MATTHIAS 2,832,860

DISCONNECT MECHANISM Filed Aug. 6, 1956 4 Sheets-Sheet 1 v INVENTORATTORNEY April 29, 1958 H. MATTHIAS 2,832,860

DISCONNECT'MECHANISM Filed Aug. 6, 1956 4 Sheets-Sheet 2 M /K M ATTORNEYApril 1958 H. MATTHIAS 2,832,860

DISCONNECT MECHANISM Filed Aug. s, 1956 4 Sheets-Sheet 4 INVENTORATTORNEY United States Patent tvcl DISCONNECT MECHANISM Lynn H.Matthias, Fox Point, Wis., assignor to Allen- Bradley Co., Milwaukee,Wis., a corporation of Wisconsin Application August 6, 1956, Seriai No.692,245

12 Claims. (Cl. 200-(l) gaged with the movable contact means uponclosure of I the cover, which handle may occupy three positionscomprising an on position wherein the contact means are placed incircuit closing position, on oil position in which the contact means areplaced in circuit interrupting position and an open position wherein thecontact means are placed in the visual observation position, theinvention further providing that in normal operation the cover canneither be closed nor opened unless the handle be in open position andthe contact means be in the visual observation position.

Disconnect switches are commonly placed between power lines and motorsand motor controls, to provide a means for disconnecting the motor andcontrols from the line. As such, disconnect switches are manuallyoperated, and are usually left in a circuit closing position unlessinspection or service work upon the apparatus powered through the switchis to be performed. At such times the disconnect switch is opened, andreliance is thus placed upon the disconnect to render the equipment tobe serviced harmless and free of line voltage.

Occasions arise where overload currents cause the dis connect contactsto weld, and a manual operation of the disconnect actuating handle isnot accompanied by a circuit interruption. Since disconnect contacts areusually housed within arc extinguishing chambers, personnel may beunaware of any malfunction, and may then be dangerously exposed to linevoltages. It is an object of this invention to have a contact positionin which contact condition may readily be observed, after the actuatinghandle has been moved for circuit interruption, to permit a person toassure himself of the circuit condition. In this manner the disconnectswitch more fully plays its function as a safety switch in the circuit.

It is another object of this invention to provide a disconnect switchhaving an arc extinguishing chamber for the contacts wherein circuitinterruption is accomplished with the contacts being housed within thechamber and wherein contacts may be removed from the chamber aftercircuit interruption to permit visual inspection.

It is another object of this invention to provide an actuating handle onthe exterior of a housing for a disconnect wherein both the handle andthe disconnect contacts have three normal positions of rest, one of thepositions placing the disconnect contacts beyond circuit interruptingposition for visual observation.

'ice

It is another object of this invention to provide a disconnect switchWith an enclosure wherein the enclosure may normally be opened or closedonly when the switch contacts are in a position beyond circuitinterrupting position.

It is another object of this invention to provide a disconnect switchhaving additional safety features to give greater protection topersonnel.

It is another object of this invention to provide a disconnect switch inwhich a pivotal movement of an actuating handle effects a linearmovement of an intermediate member to operate the switch contacts with asmooth operation minimizing wear of contacts.

The foregoing and other objects and advantages of this invention willappear from the description to follow. In the description reference ismade to the accompanying drawings, which form a part hereof, and inwhich there is shown by way of illustration and not of limitation aspecific form in which the invention may be embodied.

in the drawings:

Fig. l is a front view in elevation with parts broken away of adisconnect and enclosure embodying this inven tion,

Fig. 2 is a side view in elevation with parts broken away of thedisconnect and enclosure shown in Fig. 1,

Fig. 3 is a fragmentary view of actuating apparatus on the interior sideof the cover of the enclosure viewed from the rear,

Fig. 4 is a fragmentary view of the cover and elements mounted thereontaken on the plane 44 indicated in Fig. 1,

Fig. 5 is a front view of a hub on the front of the cover for supportingthe actuating handle, with the nave of the handle removed,

Fig. 6 is a front view in elevation with parts broken away of thecontact assembly mounted within the enclosure.

Fig. 7 is a view in section of the contact assembly taken on the plane7-7 indicated in Fig. 6,

Fig. 8 is a View of contact actuating elements taken on the plane 8-Sindicated in Fig. 6, and

Fig. 9 is a view of the elements shown in Fig. 8 in a position differingfrom that of Fig. 8.

Referring now to the drawings, there is shown in Figs. 1 and 2 a cabinet1 that comprises a shell 2 open at the front and a cover 3 hinged to theshell so that it may be swung between open and closed positions.Suitable screws 4 are provided on the cover 3 for securing the cover 3in its closed position. The cabinet 1 encloses three distinct circuitelements. Mounted in the top or" the shell 2 is a disconnect switch 5,intended for connection to power lines introduced within the cabinet 1.Beneath the disconnect 5 is a fuse block 6, and beneath the block 6 isan electromagnetic switch 7. The combination of the elements 5, 6 and 7is commonly employed in the control of an electric motor, for a machinetool or other form of power apparatus, requiring frequent switching ofthemetor. The fuse block 6 and electromagnetic switch 7 are shown indotted lines as they do not play a part of this invention and areincluded in the description by way of illustration of one form ofapparatus in connection with the disconnect of this invention may beemployed.

On the outer face of the cover 3 is mounted a hub 8, more clearly shownin Figs. 4 and 5, that has an open center and which is secured in placeby a set of three mounting screws 9 threadedly received by the cover 3.A spacer washer it) and position indicating plate 11 are held betweenthe hub 3 and cover 3. As indicated in Fig. 1 the plate 11 carries themarkings designated C011,! fi6ofii,$ locki iopen.7! I

A central boss 12 at the rear of the hub 8 extends eral side of the hub8 is a plurality of inclined grooves 13. As shown in Figs. 4 and 5, oneof the grooves 13 is out directly rearward to partially encircle a pivotpost 14 that has a head end visible from the front of the cabinet 1, andwhich extends through the spacer washer 10, the position indicatingplate 11 and the cover 3 to the interior of thecabinet 1. The outwardlyfacing head end of the pivot post 14 is provided with a slot so that itmaybe pivoted by a screw driver or similar instrument. As is also shownin Figs. 4 and 5, a thin flat ring 15 may be inserted in a complementarygroove 16 in the front face of the hub 8. The ring 15 is provided with apair of radially extending ears 17 that cover a pair of the slantinggrooves 13. The purpose of this construction will be more fullyexplained hereinafter.

Mounted upon the hub 8 is an actuating handle 18 having a nave 19covering the hub 8, from which depends a shank 20 formed to be graspedby the hand. integrally formed with the actuating handle 18 is a stubshaft 21, shown in Figs. 4 and 5, that is extended through the opencenter of the hub 8 to within the interior of the cabinet 1. The nave 19is provided on its face with three slotlike openings 22 located to formextensions of the grooves 13 of the hub '8, upon placement of the handle18 in a position of alignment. The nave 19 is also formed with threerecesses 23 in its side, that correspond with the openings 22 to providethree sets of openings and recesses. The recesses 23 also formcontinuations of the slanting grooves 13, so that upon placement of thehandle 18 in a position aligning an opening 22 and its correspondingrecess 23 with a groove 13 there will be provided a passage throughwhich the shank of a. padlock may be passed, for the purpose of lockingthe handle in fixed position. In the illustration of the invention thehandle may be placed in the position identified as lock on the positionindicating plate 11, for alignment of the three sets of openings 22 andrecesses 23 with the slanting grooves 13. Thus, there is provision forsecuringthe handle .with three separate padlocks, as is a commonlyobserved'practice in the manufacture of disconnects. If the handle bemoved to the 011" position two sets of the openings 22 and recesses 23will align with a pair of the slanting grooves 13. If the ring 15 be inplace these particular grooves 13 will be masked, to preclude insertionof padlocks. However, if it is desired to permit locking of the handlein the on position the ring 15 may be removed, through a partialdisassembly. Upon placement of the handle 18 in the on position thethird set of openings 22 and recesses 23 aligns 1 with the pivot post14, to allow a screw driver to be engaged with the pivot post 14, for apurposeto be described.

The inner end of the stub shaft 21 has a rectangularlike end boss 26,shown in dotted lines in Figs. 3 and 5, and an arm 25 fits over the endboss 26 for rotation therewith. The arm 25 narrows as it extendsradially outward, and at the end there are formed two spaced turned earsthat extend rearwardly, when the cover 3 is closed. A shallow circularneck piece 28 including a pair of spaced circular flanges 29 is fixed onthe arm 25 in a position concentric with the axis of the stub shaft 21.A bolt 24, threadedly received by the inner end of the shaft 21, retainsthe arm 25 and neck piece 23 in place. A spring washer 27 is insertedbetween the inner face of the cover 3 and the arm 25.

A plate 31 having an arcuate slot 32 encircles the shallow neck 28 ofthe arm 25 and has a close fit between the flanges 29, that form a partof the neck piece 28. The plate 31 extends to both sides of the slot 32,and spaced close to the slot 32 is a generally horizontal slot 33 inwhich the ears 3! of the arm 25 are received. The side of the plate 31,opposite that in which the slot 33 is located, tapers and terminateswith a recess 34. The recess 34 fits about a fixed pin 35 secured to,the inside of the cover 3. The pin 35 acts as a pivot point for theplate 31, so that upon a rotation of the actuating handle 18 the coupledarm 25 will swing the cars 36 to impart a rotational movement to theplate 31 about the pin 35. Also, the curvature of the slot 32 isselected so that its interaction with the neck piece 23 causes agenerally horizontal sliding movement of the plate 31, in addition tothe swinging movement about the pin 35. This dual movement causes theend 36 of the plate 31, which is opposite the end of the recess 34, tohave a compound movement. The end 36 of the plate 31 is provided withtwo spaced rearwardly extending ears 37 with a gap 38 therebetween. Apin 39 riveted to one of the upstanding ears 37 completes the plate 31.The compound movement of the plate 31 causes a pronounced verticaltravel at the end 36 with a minimum or horizontal shift. The apparatusis dimensioned so that this vertical travel at the center of the gap 38assumes nearly a straight line upon pivot of the actuating handle 13.

A member 40, formed of fiat stock, is attached on the inside of thecover 3 to the pivot post 14. The member 43 comprises a leg portion 41,attached at one end to the post 14 by a screw 44 as shown in Fig. 3,which widens from the leg 41 and is then turned rcarwardly to form aflange 42 at the opposite end. The flange 42 is turned at its rear edgeto present a blocking lip 43 of substantial vertical extent. The member43 is free to pivot with the pivot post 14- and a bias spring #35 urgesthe member 49 upwardly against a stop 46, standing inwardly from thecover 3. By means of rotation of the pivot post Ed the member may berotated downwardly against the spring 45 to place the blocking lip 43 inthe position shown in phantom in Fig. 3.

Referring now in particular to Figs. 6 and 7, the disconnect 5 isprovided with a pair of left side and right side base brackets 47 andmounted at the back of the shell 2. A set of mounting bolts 49 passthrough and secure a molded terminal block 5% to the base brackets 47,48. The terminal block 5% is formed with thr e contact receivingcavities 51, and in each of the cavities 51 is disposed a pair ofstationary contacts 52 secured to terminal strips 53 leading outwardlyfrom the cavities 51 to terminate in exposed ends carrying terminalscrews 54. The terminal strips 53 are clearly shown in Figs. 6 and 7.Along the rear of the block 59 and behind each of the cavities 51extends a cross bar 56 molded insulating material which has threeintegral legs 55. Each leg 55 runs forwardly through an opening in theblock 5-) into a cavity 51, and a thin metallic finger .59 extends fromeach leg 55. A bridging contact 57 and a contact spring 5 3 is mountedupon each leg 55, by being passed over the associated finger 59. Caps6%) hold the springs 53 and bridging contacts 5'. in place. The crossbar 56 has a fore and aft path of movement that carries the contacts 57into and outwardly from the respective cavities 51, and as may beobserved from Fig. 7 each cavity 51 is open at thefront side, oppositethe stationary contacts 52, to permit entry and exit of the contacts 51.Thus, the bridging contacts 57 may occupy three distinct positions, thefirst being a position of engagement with the stationary contacts 52 forclosing a circuit, the second being a circuit interrupting positionspaced from the stationary contacts 52, but within the cavities 51, andthe third being beyond the circuit interrupting position to a positionoutside the terminal block 50, as shown in 'Figs. 2 and 7, wherebyvisual observation of contact position may be readily made.

The terminal block is molded from a material se lected for its. arcquenching charactreistics, and for interrupting the arc upon opening thecircuit the bridging contacts 57 are retained within the cavities 51.Maximum advantage is thus taken of the are extinguishing ability of thematerial of the terminal block 50, and the cavities 51 may be termed arcextinguishing chambers. The circuit interrupting position, wherein themovable contacts are retained within the cavities 51, is shownin'phantom in Fig. 7. Upon occasion, however, the movable contacts of adisconnect become welded to the stationary contacts, and do not separateto open the circuit. Personnel are then exposed to line voltages uponentering the cabinet, or working upon the circuit serviced through thedisconnect. It is a purpose of this invention to insure protection ofpersonnel by providing a position for the movable contacts in which theymay be visually observed upon opening. the cabinet, to permit positiveidentification of the contact condition. This has not been possible inconstructions burying the contacts within arc extinguishing chambers. Toaccomplish the foregoing purpose the cavities 51 are open ended, as hasbeen described, and introduction of a readily observable contactposition beyond the circuit interrupting position is introduced.

To operate the movable contacts 57 the cross bar 56 is mounted upon arod 61 carried by a pair of supporting levers 62 pivoted to a shaft 63extending between the base brackets 47, 48. One end of the rod 61 isattached to an index plate 64 pivoted upon an end of the shaft 63. Theindex plate 64 has a set of three detents 65, 66 and 67 clearlyillustrated with reference to Figs. 8 and 9. A roller 68 is mounted on aflange shaped arm 69 that rotates about a shaft 70, secured by andextending between the base brackets 47, 48. The roller 68 rides on theindex plate 64 for engagement with the detents 65-67. A wound torsionspring 71 encircles the shaft 76, and has one end fixed by engagementwith the bracket 48 with the other end acting upon the arm 69 to firmlyseat the roller 68 in a detent 65-67. The index plate 64 is thus held inone of three positions, depending upon the particular detent 65-67brought beneath the roller 68.

As the index plate 64 is pivoted about the shaft 63, to move one of thedetents 65-67 from beneath the roller 68 and to bring another detent65-67 into position for engagement by the roller 68, the rod 61 is movedforwardly and rearwardly to impart movement to the cross bar 56, andhence to the bridging contacts 57. When the roller 68 rests within thedetent 65 the bridging contacts 57 are moved into circuit closingposition, in which they engage the stationary contacts 52. When theindex plate 64 is rotated to bring the detent 66 into engagement withthe roller 68 the bridging contacts 57 are moved to the circuitinterrupting position, in which they are still housed within the arcextinguishing chambers formed by the cavities 5'1. Upon movement of theindex plate 64 into the position in which the etent 67 is engaged by theroller 68 the bridging contacts 57 are moved tothe visual inspectionposition shown in Figs. 2 and 7.

An operating lever 72, formed from fiat stock, is pivotally mounted onthe shaft 63 immediately adjacent the index plate 64. The lever 72 has ahead portion 73 presenting a forward edge 74, and secured to the headportion 73 is a roller 75 adapted to fit within the gap 38 formed by thespacing of the ears 37 on the end 36 of the plate 31. A Window 76 is cutin the operating lever 72 and a similar adjacent window 77 is formed inthe index plate 64. A compression spring 73 is inserted within the twowindows 76, 77, so that upon a movement of the operating lever 72 thecompression spring 78 will be loaded in compression to urge the indexplate 64 to follow the movement of the operating lever 72. The operatinglever 72 is further formed with a pry 79, shownv in Figs. 6, 8 and 9,disposed to engage the roller 68 and lift it out of a detent 66-67 whenthe lever 72 is moved to shift the bridging contacts 57 into or awayfrom the visual observation position. To complete the structure a pin itstands out from the side of the index plate 64 in the path of theoperating lever 72, and abutment edges 81 and 82 are provided on theoperating lever 72 to strike the pin 80, for moving the index plate 64with the operating lever 72, after loading of the spring 78, as willhereinafter be discussed.-

To close the cover 3, when it is open, the actuating handle 18 must bemoved to its open position, and the operating lever 72, of thedisconnect 5, must be moved to its lowermost position, corresponding tothe visual observation position of the bridging contacts 57, in whichthe detent 67 is engaged by the roller 68. Upon closure of the cover 3the roller 75, of the lever 72, is received within the gap 38 of theplate 31. If the actuating handle 18 be in a position other than itsopen position, the pin 39 on the end 36 of the plate 31 will strike theforward edge 74 of the head portion 73 of the operating lever 72,thereby precluding full closure of the cover 3. If the operating lever72 be in a position other than the one of engagement of the detent 67with the roller 68 the roller '75 will be struck by the blocking lip 43on the member 46, again precluding full closure of the cover 3. T has,the cover 3 may be closed only when the bridging contacts 57 of thedisconnect 5 are in the visual observation position, insuring that linevoltages may not be applied to apparatus serviced through the disconnect5, until the cover 3 is fully closed.

With the cover 3 closed, the actuating handle 18 may be moved to its offposition. This causes an upward movement of the end 36 of the plate 31,whereby the roller 75 of the operating lever 72 is likewise carriedupwardly. As the operating lever '72 is moved the pry 7%, which at thispoint in the operation is immediately adjacent the underside of theroller 63 as shown in Fig. 6, moves the roller 63 out of the detent 67.The coupling of the index plate 66 with the operating lever 72, throughthe compression spring 78, causes the index plate 64 to rotate with thelever 72 and bring the detent 66 beneath the roller The pry 79 passes tothe rear of the roller 63, and the wound torsion spring 71 will thenmove the roller 63 into en agement with the detent 66 with a snapaction. The index plate 64 is now held in the position in which thebridging contacts 57 are in the circuit interrupting position, spacedfrom the stationary contacts 52, but within the cavities 51. Thisposition is shown in phantom in Fig. 7. r

If the actuating handle lid now be moved to its on position the bridgingcontacts 57 will be brought into engagement with the stationary contacts5'2. The movement of the operating lever '72, occasioned by movement ofthe handle i8, loads the compression spring 78, since the roller 68inhibits the index plate 64 from following the initial movement of theoperating lever 72. Upon loading the compression spring 76 the abutmentedge 31 of the operating lever 72 strikes the pin 81?, to carry theindex plate 64 with the operating lever 72 and raise the rolier 63 outof the detent 66. In Fig. 9 the elements are shown at the point ofoperation where the index plate 64 has been moved to raise the roller68. At this point the loaded compression spring 78 abruptly moves theindex plate 64 and imparts a rapid circuit closing movement to thecontacts 57. The detent 65 is moved beneath the roller 6%, and the woundtorsion spring 71 then drives the roller 63 into engagement with thedetent 65 to firmly retain the index plate 66in position.

In moving the actuating handle 18 in the reverse direction, that is fromits on position through the off to the open position, the bridgingcontacts 57 will be moved in reverse sequence, from circuit closedposition to circuit interrupting position and then to the visualinspection position. The movement of the bridging contacts 57 from thecircuit closed position to the circuit interrupting position isaccomplished by an initial loading of the compression spring '78,followed by the abutment edge 32 striking the pin 89 and then a movementof the index plate 64 to raise the roller 68 from the detent 65. Theloaded spring 76 causes a rapid contact separation and the roller 68engages the detent 66 to hold the contacts 57 from the stationarycontacts 52, but within the arc extinguishing cavities 51.

Uponreturning the bridging contacts 57 to the visual inspection positionthe pry 7? is again brought into operation. The pry 79 is adjacent theroller 68, as shown in Fig. 8, and movement of the lever 72, in responseto the actuating handle 18 being moved to open" position. carries thepry 79 against the roller 68. The roller (58 is raised out of the detent66, and the compression spring 78 will, without being fully loaded,cause the index plate 64 to follow the lever 72. The detent 67 is thenengaged by the roller 68 and the bridging contacts are moved into avisual inspection position whereby they may be readily observed, uponopening the cover 3, to determine that the circuit is open. The pry 79is utiiized when the bridging contacts 57 are moved into or out of thevisual inspection position. For these movements of the bridging contacts57 rapid snap action, necessary during switching, is not required, andhence full loading of the compression spring '78 is dispensed with.

It should be observed that movement of the open-ding lever 72 away fromthe position ccrresponi visual inspection position of the bridging contries the roller '75 upwardly in front of the blocking lip 43 of themember 4%. Opening of the cover 3 is then precluded, since the blockinglip 4-3 will strike the roller 75. Provision, however, is made to permitopening of the cover 3 when the bridging contacts 57 are in circuitclosing position by informed personnel particularly acquaintcd with theconstruction of the apparatus. When the handle 18 is in on position ascrew driver may be engaged with the pivot post 14, and rotated to turnthe post 14 and the member 49 to the position shown in phantom in Fig.3. in this position, the blocking lip 43 is moved from behind the roller75, to free the cover 3. Special service personnel may thereby haveaccess to the interior of the cabinet 1, when the circuit serviced bythe disconnect 5 is closed, in the event occasion should arise for suchan inspection.

When servicing and repairing equipment connected to power lines throughapparatus of the invention, it is often desirable to lock the disconnect5 in the circuit interrupting position. This is accomplished by movementof me actuating handle 13 to the oii position, and then slightly beyondthe off position to bring the openings and recesses 22-23 into alignmentwith the slanting grooves 13 of the hub 8. Insertion of the shank or apadlock may then be made to secure the cover 3 closed with thedisconnect 5 in circuit interrupting position. As has been heretoforenoted provision is made for three such padlocks. Also, if the ring 15 beremoved the handle may be locked in the on position, with the contactsin the circuit closing position.

The invention provides for a disconnect in which the contacts have anadditional position beyond a circuit interrupting position in whichtheir physical position may readily be identified. An actuating handleis cooperatively related with the contacts, and a cabinet for thecontacts may normally not be entered until both the handle and contactsare moved to positions beyond the positions for circuit interruption.

I claim: I

1. In a disconnect mechanism the combination comprising stationarycontact means; movable contact means engageable with and disengageablefrom said stationary contact means; and indexing operating means in mechanically movable connection with said movable contact means and beingadapted to actuate said movable contact means to occupy three indexpositions including a circuit closing position in engagement with saidstationary con tact means, a circuit interrupting position spaced fromsaid stationary contact means, and a visual inspection position beyondthe circuit interrupting position.

2. In a disconnect mechanism the combination comprising stationarycontact means; movable contact means engageable with and disengagcablefrom said stationary contact means; and operating means for saidmow ablecontact means adapted to cause said movable contact means to occupy acircuit closing position in engagement with said stationary contactmeans, a circuit interrupting position spaced from said stationarycontact, and a visualv inspection position beyond the circuitinterrupting position, wherein said operating means comprises an indexplate cooperatively engaged with said movable contact means for movingthe same and having a set of three detents; a retaining member adaptedto move into engagement with a detent for retaining the index plate in afixed position; an operating lever for moving said index plate wherebythe detents may be successively moved into engagement with the retainingmember to define three index plate positions corresponding to saidcontact positions; resilient means interposed between said index plateand operating lever whereby movement of the lever loads the resilientmeans and urges the index plate toward a successive position; abutmentmeans interposed between the index plate and lever to carry the indexplate with the lever upon loading the resilient means to initially movethe index plate against the retaining member when moving the index platefor causing engagement or disengagement of said stationary and movablecontact means; and a pry on said lever that dislodges said retainingmember from a detent upon moving the lever to alter the index plateposition to or from the position corresponding to visual inspectionposition of said movable contact means.

3. In a disconnect mechanism the combination com prising stationarycontact means; an arc extinguishing chamber disposed about saidstationary contact means and having an opening opposite the stationarycontact means; movable contact means engageable with and disengageablefrom said stationary contact means which has a movement extending fromwithin said arc chamber through said opening to the exterior of the arcchamber; and indexing operating means in mechanically movable connectionwith said movable contact means and being adapted to actuate saidmovable contact means to occupy three index positions including acircuit closing position in engagement with said stationary contactmeans, a circuit interrupting position within said are chamber spacedfrom said stationary contact, and a visual inspection position beyondthe circuit interrupting position that is outside said are chamber.

4. In a disconnect mechanism the combination comprising stationarycontact means; an arc extinguishing chamber disposed about saidstationary contact means and having an opening opposite the stationarycontact means; movable contact means engageable with and disengageablefrom said stationary contact means which has a movement extending fromwithin said are chamher through said opening to the exterior of the arcchamber; and operating means for said movable contact means adapted tocause said movable contact means to occupy a circuit closing position inengagement with said stationary contact means, a circuit interruptingposition within said are chamber spaced from said stationary contact,and a visual inspection position beyond the circuit interruptingposition that is outside said are chamber wherein said operating meanscomprises an index plate cooperatively engaged with said movable contactmeans for moving the same and having a set of three detents; a

ctaining member adapted to move into engagement with a detent forretaining the index plate in a fixed position; an operating lever formoving said index plate whereby the detents may be successively movedinto engagement with the retaining member to define three index platepositions corresponding to said contact positions; resilient meansinterposed between said index plate and operating lever whereby movementof the lever loads the resilient means and urges the index plate towarda successive position; abutment means interposed between the index plateand lever to carry the index plate with the lever upon loading theresilient means to initially move the index plate against the retainingmember when moving the index plate for causing engagement ordisengagement of said stationary and movable contact means; and a pry onsaid lever that dislodges said retaining member from a detent uponmoving the lever to alter the index plate position to or from theposition corresponding to visual inspection position of said movablecontact means.

5. In a disconnect mechanism the combination comprising stationarycontacts; an arc extinguishing chamber disposed about said stationarycontacts having an entrance opposite the stationary contacts; movablecontacts engageable with and disengageable from said stationary contactswhich have a movement extending through said entrance; indexingoperating means in mechanically movable connection with said movablecontacts and being adapted to actuate said movable contacts to occupythree index positions including a circuit closing position in engagementwith said stationary contacts, a circuit interrupting position withinsaid arc chamber that is spaced from said stationary contacts, and aninspection position outside the entrance of said are chamber; anenclosure with a cover housing said contacts and operating means; anactuating handle on the exterior of said enclosure having an onposition, an cit position and an open position, said handle beingcooperatively engaged with said indexing operating means to actuate thesame whereby handle on position corresponds to circuit closing positionfor said movable contacts, handle cit position corresponds to circuitinterrupting position, and handle open position corresponds toinspection position; and interlock means precluding opening of saidcover unless said handle is in open position.

6. A disconnect mechanism in accordance with claim having blocking meansprecluding full closure of said cover unless said handle is in openposition and said indexing operating means is placed to move saidmovable contact means to said inspection position.

7. In a disconnect mechanism the combination comprising an enclosurehaving a mounting shell and a cover; a disconnect switch within saidmounting shell having stationary contacts and movable contacts, whichmovable contacts have a closed position with said stationary contacts,an open position spaced from the stationary contacts, and an inspectionposition beyond the open position; an operating mechanism inmechanically movable connection with said disconnect switch having threepositions of index for causing movable contacts to occupy said closed,open and inspection positions, and ineluding an operating leverextending toward said cover; an actuating handle on the outer side ofsaid cover having three positions corresponding to the positions of saidmovable contacts; and intermediate means on the inner side of said covercooperatively connected to said handle and engageable with saidoperating lever when said cover is closed to transmit motion from thehandle to the lever.

8. An apparatus in accordance with claim 7 wherein said actuating handleis pivotally mounted on the outer side of said cover with a shaftextending through the cover; and said intermediate means comprises: anarm mounted on said shaft on the inner side of said cover for turningmovement with said handle; a guiding neck coaxial with said shaftlocated 011 the inner side of said cover; a plate having an arcuate slotencircling said neck and extending to both sides of the slot with alever engaging end at one side; a sliding connection between the end ofsaid arm and said plate; and a stationary pivot it) slideably engagingsaid plate at the end thereof opposite said lever engaging end.

9. In a disconnect mechanism the combination C0111- prising an enclosurehaving a mounting shell and a cover; a disconnect switch within saidmounting shell having a first set of contacts and a movable set ofcontacts, which movable contacts have a closed position with said firstset of contacts, an open position spaced from the first set of contactsand an inspection position beyond the open position; an arcextinguishing chamber for said contacts surrounding both the first setand the movable contacts when the movable contacts are in open positionand receding from a surrounding position of the movable contacts for theinspection position of the movabie contacts; and an operating mechanismfor said movable contacts including contact indexing means operativelyengaged with said contacts, an actuating handle on the outer side ofsaid cover having an on position, an off position and an open positionbeyond the OE position, and intermediate means on the inner side of saidcover operable by said handle and engageable with said indexing means tomove said movable contacts in response to actuating handle movementwhereby the contact positions of closed, open and inspection corre spondrespectively to on, off and open positions of said handle.

10. An apparatus in accordance with claim 9 having a blocking memberwithin said enclosure attached to said cover and a catch member attachedto said intermediate means movable into alignment with the blockingmember when said handle is moved to on" or off position thereby blockingopening of said cover, and said catch member being moved from a positionof alignment with the blocking member when said handle is moved to openposition to permit opening and closing of said cover.

11. In a switch the combination comprising a first contact; a movablecontact engageable with and disengageable from said first contact; anindex member cooperatively engaged with said movable contact to impartmotion thereto which motion is toward and from engagement with saidfirst contact; a retaining member adapted to engage with the indexmember to define a plurality of determined positions for the indexmember and hence for the movable contact; an operating lever for movingsaid index member between said determined position; resilient meansinterposed between said lever and said index member whereby movement ofthe lever loads the resilient means thereby urging the index memher to asuccessive determined position; and abutment means between the lever andthe index member adapted to make an initial movement of the index membertoward the successive determined position after a loading of theresilient means whereby the resilient means causes completion ofmovement to such successive determined position.

12. A switch in accordance with claim 11 wherein the lever has a prythat moves the retaining member with respect to the index member topermit movement of the index member with a reduced loading of theresilient means upon moving the index member into one of said determinedpositions.

References Cited in the file of this patent UNITED STATES PATENTS2,383,296 Dorfman Aug. 21, 1945 2,504,775 Wood Apr. 18, 1950 2,673,260Lester et a1. Mar. 23, 1954 2,695,934- Wills Nov. 30, 1954

